Torchless self-adhesive roofing product and method

ABSTRACT

A roll roofing product includes an elongate strip of inorganic fibrous base sheet impregnated with asphaltic matrix. An upper side of the base sheet is longitudinally divided into two elongate lateral portions each about one-half the width of the base sheet, but one being slightly wider than the other. On the under side the base sheet is similarly longitudinally divided into two elongate lateral parts each about one-half the width of the base sheet, but one being slightly wider than the other. The wider portion and the wider part are not congruent with one another. The narrower portion is coated with a cover layer of protective coarse granular material, while the wider portion is coated with fine-dimension granular material effective to prevent the base sheet from self adhering when rolled up on itself. The wider part is coated with a layer of asphaltic adhesive, while the narrower part is also coated with a layer of fine-dimension granular material also effective to prevent the base sheet from self adhering when rolled up on itself. When installed on a roof in plural partially overlapping strips, the roofing material is overlapped a little more than about 50% to everywhere provide dual coverage, and also to provide a duality of sealing bonds preventing permeation of the roof by water. One sealing bond is formed between the layer of asphaltic adhesive on the wider part of an overlying strip of the roofing material and the wider portion of an overlapped strip of the roofing material. The fine-dimension granular material on this wider portion does not prevent bonding by the adhesive. The other sealing bond is formed by the asphaltic adhesive and the deck of a roof on which the roofing material is installed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to roofing. More particularly, this invention relates to a self-adhesive waterproof membrane or roofing material, which is particularly suited for application to flat or slightly pitched roofs and which requires no torching operation for its installation. Such a roofing product is generally of the type employed on commercial, industrial, and large multi-unit residential structures. However, use of this roofing product and method on smaller structures and residences is not excluded from the present disclosure. Still more particularly, this invention relates to a roofing product and method having an installation that is substantially free of Volatile Organic Compounds (VOC's), and which is applied to a building substantially without the use of torching or molten tar. Rather, the roofing material is pressure-sensitive, and is pressed into place and is further secured with roofing fasteners. Thus, concerns of air pollution, worker safety, and possible structural fire, are substantially eliminated by use of this invention.

2. Related Technology

Generally, the roof structure of a building which employs a substantially flat or only slightly pitched roof includes a structural portion, which may include roof beams or trusses, possibly a grid of stringers carried on the beams or trusses, and a roof deck or sheeting which is carried on the stringers. The roof deck or sheeting may be carried directly upon the roof beams or trusses in some roof structures. Upon this structural portion is generally disposed an outwardly (i.e., upwardly) exposed water proof membrane (i.e., the roofing material). The water proof membrane structure prevents water (i.e., from precipitation) from penetrating the roof structure. Generally, the roof is provided with a system of drains, and possibly a system of gutters, along with drain pipes or down spouts, to carry precipitation water away.

Such a roof structure may be substantially flat, or may be slightly pitched. Further, such a roof structure frequently has plural vent pipes (i.e., for ventilating, heating, and air conditioning of the building, for example), ventilator fans, air conditioning units, heaters, electrical service conduits and cable ducts, electrical transformers and switch gear, and other utility devices and facilities mounted on the roof, and with portions of these facilities and devices passing through openings in the roof structure.

Historically, such flat or slightly pitched roofs have been of “built up” construction. That is, after the structural portion of the roof is completed, one or more layers of “tar paper” in the form of strips or sheets from a roll would be put down on the roof decking or sheeting, and one or more layers of roll sheet roofing material would be applied over the “tar paper.” The strips of roll roofing material are slightly overlapped at their edges, and the roof membrane may include several layers of such overlapped strips with the strips in each successive layer all running horizontally. The roll roofing material is generally applied with molten tar, in what is known as a “hot mop” process. As used herein, “tar” refers to any of various dark-colored viscid products obtained by the destructive distillation of certain organic substances, such as coal or wood, coal tar pitch, viscid asphaltic materials, etc., and is used without limitation on the invention.

Further, the conventional roll sheet roofing is usually about 3 feet wide (or about one meter if metric sized), is utilized at a roofing site in the form of a rolled elongate strip which may be 15 feet or more in length, and would generally be applied by a “hot mop” method as mentioned above. In such a “hot mop” method hot molten tar may be carried by hand in buckets up a scaffolding, or may be pumped from a tar kettle (i.e., a tar heater and pump unit) on the ground, in order to be delivered by a temporary pipe line arrangement to the roof. This hot tar is then mopped or otherwise spread on the seams and over the face of the sheet roll roofing to seal the seams and provide an additional water proof layer. Generally granular mineral material is spread over the surface of the roof to provide protection for the tar from ultraviolet radiation in sun light.

Some forms of conventional roll sheet roofing have granular material already applied over most of the outer face of the strip of roofing material, and the seams between adjacent strips of this roofing may be formed by a “torch down” method. In such a “torch down” method, after a strip of roofing is put down, a pre-applied strip of tar on the top elongate edge of this one strip of roofing is heated and softened with a large torch immediately before the side marginal edge portion of the next-successive strip of the roll sheet roofing material is put down on the roof structure.

Understandably, such conventional roofing practices which involve the use of hot molten tar, and of large torches, frequently result in a worker being burned by the tar or torch. Further, as is well understood by anyone who has been within even a few hundred feet of such a roofing project, the use of hot molten tar releases large amounts of noxious VOC's into the atmosphere.

Still further, molten roofing tar is flammable, and roofing torches provide a ready ignition source. Consequently, the conventional torch methods of roofing installation have resulted in many roof fires, and in structure fires when a roofing fire spreads before it is contained. Even in cases in which a roof fire results but is stopped before it spreads to the structure, the roofers are at risk of injury as they attempt to put out the fire. In some areas, local fire departments and Fire Marshals require torch roofing projects to be carried out under a “hazard watch” condition, in which local fire stations are informed of the project, and have an emergency response plan worked out ahead of time for use in the event that a roof fire starts.

As a result, recently a new form of roll sheet roofing has come into use. This newer roll sheet roofing is intended to be pressure sensitive and “self adhesive.” That is, in much the same way that an adhesive bandage is applied to the skin by first removing a release sheet to uncover a layer of sticky pressure-sensitive mastic adhesive, such “self adhesive” roll sheet roofing materials are provided with a layer of sticky adhesive on the underside of the roofing material. This sticky adhesive is covered by an elongate strip of release sheet material, which may be a plastic film of a type that does not bond permanently to the adhesive material, for example. In the use of such a “self adhesive” roll roofing material, as each successive strip of roofing material is unrolled the release sheet is pulled off and the adhesive material on the underside of the strip secures it to the underlying roof structure. The adhesive material is capable of bonding to the underlying roof structure so that the successive strips are placed side by side and appear to form a lap joint between them.

That is, although experience has shown that this “self adhesive” roll sheet roofing material solves many problems of the old “hot tar” roofing materials and methods, it has new problems and deficiencies of its own. In other words, the “self adhesive” roofing materials have limitations with respect to the conditions under which they can be successfully applied. If the conditions of application are too cold (i.e., below about 55° F.) or too wet, then the self adhesive roofing materials will not adhere well to the underlying roof structure. This limitation is understandable in view of the fact that the adhesives generally utilized on the self adhesive type of roll roofing materials is viscous and must soften (i.e., become viscid) to engage and bond with the underlying roofing materials. Further, rain, snow or other precipitation falling on the roof before the seams have bonded may seep through the seams. The presence of such moisture further will delay or interfere with the bonding of the adhesives generally employed on self adhesive roofing materials. In such cases the self adhering roofing materials have been known to not satisfactorily adhere to the underlying roof structure. In the event of such a less than satisfactory adherence of the self adhering roofing materials, if a strong wind storm takes place while the roof materials are not securely adhered then some or all of the new roofing materials may be blown off of the roof. With the conventional self adhesive roofing materials, when an application must be made during ambient conditions that are too cold the hope is that the conditions will improve (i.e., become warmer) and that the new roof material will then adhere by action of its own adhesive before the new roof is exposed to a strong wind storm.

Further, the conventional self adhesive roofing materials provide only a single layer of coverage for the underlying roof structure with each layer of the material put on a roof. So, several layers may be necessary in order to achieve satisfactory weatherproofing.

SUMMARY OF THE INVENTION

In view of the deficiencies of the conventional related technology, it is an object of this invention to overcome one or more of these deficiencies.

Particularly, it is an objective for this invention to provide a self-adhesive roll roofing material that has improved moisture resistance at the seams, even when applied in cold conditions.

Accordingly, the present invention, as seen in a particularly preferred exemplary embodiment, provides a roll roofing product including an elongate strip of inorganic fibrous sheet material permeated with an asphaltic matrix; the elongate strip defines a pair of upper elongate longitudinal facial portions each about one-half as wide as the strip of sheet material. One of the pair of upper elongate longitudinal facial portions carries a covering layer of protective coarse granular material, and the other of the pair of upper elongate longitudinal facial portions carries a coating of fine-dimension granular material sufficient to prevent self adhesion of successive wraps of the strip of roofing material when rolled on itself. The elongate strip further defines a pair of lower elongate longitudinal facial parts each about one-half as wide as the strip of sheet material. And, one of the pair of lower elongate facial parts carries a coating of an asphaltic adhesive, while the other of the pair of lower elongate longitudinal facial parts carries a coating of fine-dimension granular material effective to prevent self adhesion of successive wraps of the strip of roofing material when rolled on itself.

Other objects, features, and advantages of the present invention will be apparent to those skilled in the art from a consideration of the following detailed description of a preferred exemplary embodiment thereof taken in conjunction with the associated figures which will first be described briefly.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 provides a fragmentary perspective view of a portion of a roof structure having self-adhesive roll roofing material applied thereto, and embodying the present invention;

FIG. 2 is a fragmentary cross sectional view of the roof structure seen in FIG. 1;

FIG. 3 is a somewhat enlarged cross sectional end view of a roofing material embodying the present invention and which may be used in practice of the present inventive method; and

FIG. 4 provides a diagrammatic representation schematically depicting how rolled strip roofing materials are applied to a roof structure in the practice of the present invention according to a particularly preferred embodiment.

DETAILED DESCRIPTION OF AN EXEMPLARY PREFERRED EMBODIMENT OF THE INVENTION

While the present invention may be embodied in many different forms, disclosed herein is a specific exemplary embodiment that illustrates and explains the principles of the invention. In conjunction with the description of this embodiment, a method of practicing the invention is described. It should be emphasized that the present invention is not limited to the specific embodiment illustrated.

Viewing FIGS. 1 and 2 (which respectively provide a perspective view, and an elevation view, both of which are fragmentary and partially cross sectional), and referring first to FIG. 1 for a general overview of the inventive roof structure, a typical flat or slightly pitched building roof structure 10 according to the present invention is depicted. It is to be noted that in FIGS. 1 and 2, the thickness of the roll roofing material to be further described below is illustrated with an exaggerated thickness for clarity of illustration. The roof structure 10 includes plural elongate and spaced apart roof beams or rafters 12, cooperatively supporting a roof deck 14. The roof deck 14 may be made, for example, of one or more layers of boards or plywood spanning the spaces between the rafters 12, and supported on these rafters. Supported on the roof deck 14 is a waterproof membrane structure, generally referenced with the numeral 16. This membrane structure 16 preferably includes a layer of partially overlapping (i.e., with a little more than a 50% overlap) strips of roll roofing material 18. As will be seen, the roll roofing material 18 upwardly presents an elongate exposed surface portion which is coated with protective coarse granular material which protects the roofing material from deterioration by ultraviolet rays in sun light.

Downwardly, the roll roofing material 18 presents an elongate surface portion that is coated with an adhesive material effective to sealing bond the roofing material 16 to an adjacent strip of the roofing material, and also to sealingly bond the roofing material to the roof deck 14 as will be further explained. The remaining elongate surface portions of the roofing material 18, both on the upper and lower faces, are coated with a fine granular material. That is, about half of the upper face and about half of the congruent lower face of the roll roofing material 18 is coated with the fine granular material. This fine granular material is effective to prevent wraps of the material from sticking to itself when rolled for shipping. However, an upwardly disposed surface portion of the roofing material strip (which surface portion is coated with this fine granular material) is nevertheless bondable to a successive strip of the roofing material by action of the adhesive carried on the lower face of that next-successive strip of roofing material. Importantly, as is seen in FIGS. 1 and 2, because of the overlap of adjacent strips of the material 18 being slightly more than one-half (i.e., slightly more than 50%) the roofing material 18 everywhere provided double thickness coverage for the roof deck 14, as will be further explained.

More particularly, viewing FIG. 2 in detail, it is seen that the strips 18 of roofing material on their upper faces each have a width dimension composed of two adjacent parts 18 a and 18 b, each of which represents an elongate ribbon-like portion of the roofing material strip 18. Although the invention is not so limited, according to a preferred embodiment of the invention, the parts 18 a and 18 b are about but not exactly of equal width. Further, according to the preferred embodiment, the part 18 a (i.e., an underlying portion covered by a next successive strip 18 of roofing material) is about 20 and ½ inches wide, while the part 18 b (i.e., the upwardly exposed overlying portion, covering over part of a preceding strip of the roofing material 18) is about 19 inches wide, and the strip of roofing material 18 most preferably has a width of about 39½ inches. The portion 18 a also forms a Z-shaped lap joint feature, indicated in FIG. 2 by the arrowed numerals 18 a′, but is mostly covered over or lapped over by the portion 18 b of a next successive strip 18 of the roofing material.

Conversely, the portion 18 b substantially laps over the part 18 a of a preceding strip of the roofing material 18. As is seen in FIG. 2, the extent of overlapping of each strip 18 of the roofing material 16 with a preceding strip of the material 16 is preferably a little more than about ½ of the total width of the strip of roofing material 18. That is, although the invention is not so limited, the most preferred embodiment of the inventive roofing material 18 utilizes an overlap fraction that is a little more than substantially one-half. Accordingly, each strip of the roofing material 18 most preferably overlaps a preceding strip of the material in a layer of the roofing material 18 making up a membrane 16 by about one-half (½) of the width of the strips 18, and also very slightly overlaps another underlying strip of the material 18, as is best seen in FIG. 2.

Turning now to FIG. 3, which presents a fragmentary end view of a roofing material strip 18 with portions of the width of this strip broken out for clarity of illustration, it is seen that the strip of roofing material 18 includes an elongate base sheet or strip 20 of inorganic fibrous material. The base sheet has a left-hand edge indicated with numeral 20′ and a right hand edge indicated with numeral 20″. As is seen in FIG. 3, the base sheet 20 has a width 18′ (which is about 39½ inches according to the preferred embodiment) and extends from side to side and from end to end of a strip 18 of the roofing material. That is, the base sheet 20 and the strip 18 of roofing material may be several feet long. This base sheet 20 may be made, for example, of felted, fine-dimension glass fibers, which are inter-tangled and compressed into a self-sustaining web. That is, although the sheet 20 is not woven, it does not fall apart easily, or even pull apart easily, because the fine-dimension glass fibers of this sheet are inter-tangled and pressed together. As is well understood in the pertinent arts, the sheet 20 may also be embossed, or needle-punched, for example, to improve its tenacity and cohesiveness.

Penetrated into and substantially through the sheet 20 is a matrix 22 of asphaltic material. This matrix of asphaltic material 22 adheres the fibers of the base sheet 20, and unifies the base sheet 20 and matrix 22 into a unitary durable structure. As is seen in FIG. 3, a layer 24 of raw asphaltic adhesive material is carried on a lower facial portion of the base sheet 20, and extends from the right-hand side edge 20″ over a little more than one-half the width of the base sheet 20. This layer of raw asphaltic material 24 is preferably covered by a removable plastic sheet 26. That is, the layer 24 of adhesive raw asphaltic material extends from one side edge 20″ of the base sheet 20 through a lateral dimension 28, which is a little more than one-half (½) or more of the width of the strip 18 of roofing material. Most preferably, the lateral dimension 28 is at least one-half (½) inch more than the width of the facial portion 18 a. Accordingly, the dimension 28 is most preferably at least about 20½ inches wide. The lateral dimension 28 may also be wider than 20½ inches.

On the upper face of the strip 18 of roofing material as seen in FIG. 3, this material includes a layer 30 of coarse granular material extending from the right-hand side edge 20″ through a lateral dimension 32. The lateral dimension 32 is preferably slightly more than the width of facial portion 18 b, and is also may be slightly more than one-half the width of the strip 18 of roofing material. As is well understood in the pertinent arts, the layer 30 of granular material is adhered to the base sheet 20 and matrix 22 by the application of a thin coating of hot asphalt (not seen in the drawing Figures) and the immediate sprinkling of the granular material 30 onto and slightly into this asphalt coating (i.e., by use of a pressure roll). The layer 30 of coarse granular material provides full coverage with the coarse granular material through the width of portion 18 b, and also on an additional margin of full coverage followed by a tapering off of the coverage of granular material 30 slightly onto the adjacent facial portion 18 a.

Thus, the coarse granular material 30 provides full coverage on facial portion 18 b, and also a short distance onto the facial portion 18 a. This marginal portion of facial portion 18 a is effective to form the Z-shaped transition indicated in FIG. 2 with the arrowed numeral 18 a′, which is formed at the lap joint of adjacent strips of the roofing material 18. Accordingly, most of the coarse granular material 30 (i.e., throughout the width dimension 18 b, and through most of the dimension 32) is exposed upwardly when the strips 18 of roofing material are installed on a roof. A part of the layer 30 of course granular material is covered by the next successive strip of roofing material 18. And, this layer 30 of coarse granular material not only protects the asphaltic matrix 22 from deterioration which would be caused by ultraviolet rays in sunlight, but is generally colored in various shades (and possibly is applied in a pattern of variegated colors) in order to give the roof 10 a pleasing aesthetic appearance. Most of the remainder of the upper face of the strip of roofing material 18 is covered with a fine-dimension granular material 34 extending through a lateral dimension 36. This fine-dimension granular material covers most of the facial portion 18 a.

Further, in order to insure proper overlap of the roofing material strips 18 when installed on a roof, the layer 30 will include an elongate line of longitudinally extending visual guide markers (i.e., perhaps in the form of a dashed chalk line) the location of which is generally indicated by arrow 30′ on FIG. 3, and which is disposed the correct distance from edge 20″ in order to define the facial portion 18 b. According to the illustrated exemplary preferred embodiment, the guide marks indicated by arrow 30′ are about 19½ inches from the side edge 20″. So, the facial portion 18 b is intended to measure 19½ inches from side edge 20″ while the facial portion 18 a measures about 20½ inches from side edge 20′ to the guide marks 30′.

However, on the upper face of the roofing material strip 18, there is preferably a small exception to or exclusion of the coating 34 in a marginal edge portion (or selvage edge portion) 34′. In this selvage edge portion 34′ the fine-dimension granular material 34 preferably is partially removed and/or partially pressed into the base sheet 20 and matrix 22. Accordingly, in this marginal edge portion 34′, which may be about an inch wide, for example, the thickness of the roofing material 18 is reduced or tapered toward the adjacent side edge 20′. In this selvage edge portion 34′ however, there remains sufficient fine granular material so that the selvage edge portion is not sticky and does not cause adherence of successive wraps of the material 18 when rolled for shipping. It is to be appreciated, however, that because of the reduced thickness of the selvage edge portion 34′ when the successive strips 18 of roofing material 16 are overlapped during installation on a roof, the underlying strip of material 18 provides an edge thickness at selvage edge portion 34′ that is rather thin (that is, thinner than the full thickness created by the combination of base sheet 20 and matrix 22 along with the upper and lower coatings of fine-dimension granular material 34 and 34″—coating 34″ being introduced below). This rather thin dimension at the side edge 20′ of the underlying strip of roofing material (i.e., at the edge of selvage edge portion 34′) is easily accommodated and bridged by the layer 24 of raw asphaltic material on the overlying strip 18 of roofing material, so that void spaces (which could harbor moisture and lead to blistering of the roof membrane 16) are substantially eliminated. Again, it is to be noted that the dimensions 32 and 36 are each about one-half (½) of the width of the strip 18 of roofing material, while the dimension 28 is preferably at least one-half (½) inch more than the width of the portion 18 a.

Finally, the remaining portion or part of the lower face of the strip 18 of roofing material is coated also with a layer 34″ of substantially the same fine-dimension granular material used on the upper facial part 18 a (there indicated with numeral 34). Actually, the layer 34″ of fine-dimension granular material is applied to the combination of the base sheet 20 and matrix 22 before the layer of adhesive material 24 is applied, and the width of this layer 34″ of fine-dimension granular material as applied is almost one-half of the width dimension 18′. Accordingly, because the layer 24 of adhesive material is more than one-half the width of the strip 18 it slightly overlaps this layer 34″ of fine-dimension granular material. Further, the strip 26 of removable plastic film is also slightly wider than is the layer 24 of adhesive material, both to extend slightly beyond the edge 20″ and to extend slightly beyond the coating 24 onto the coating of fine granular material 34″. Thus, a marginal edge portion 26′ of the plastic film 26 lies atop of the fine-dimension granular material of layer 38 and is not adhered. So, this loose marginal edge portion 26′ of the film 26 is easily lifted up manually in order to start pealing of the film 26 off of the adhesive layer 24 (as will be further explained below).

Turning now to FIG. 4, a step in the method of applying successive strips 18 of roofing material 18 in order to provide a waterproof membrane 16 on a roof structure deck 14 is illustrated. As is seen along the right-hand side of FIG. 4, a preceding strip 18 of the roofing material has been applied to the roof structure, and upwardly presents facial portions 18 a and 18 b. The preceding strip of material 18 is preferably secured to the roof deck 14 by three spaced apart elongate longitudinal lines of plural roofing nails or fasteners 38 (only the heads of which are visible in the drawing Figure), each line of fasteners being generally indicated by the numerals 38′. These fasteners 38 are driven through the roofing material 18 in facial portion 18 a, and the two outside lines of fasteners are preferably on 12 inch centers. On the other hand, the center line of fasteners 38 is preferably on 18 inch centers. The left hand one of the three lines 38′ of fasteners 38 is preferably spaced laterally about 3 inches from the side edge 20′, while the center line of fasteners 38 is spaced laterally about 9½ inch from the edge 20′. On the other hand, the right hand line 38′ of fasteners 38 is preferably spaced laterally about 3 inches from the adjacent edge of the coarse granular material 30 (i.e., from the adjacent edge of the portion 18 b). Each successive strip 18 of roofing material is similarly secured to the roof deck 14. As will be seen, the adhesive material 24 also has a role to play in securing the roofing material strips 18 to the roof deck 14.

Next, as is illustrated in FIG. 4, a successive strip 18 of roofing material is applied by unrolling this strip from a roll of the material (translational movement of the roll and unrolling being indicated respectively by the associated horizontal arrow and by arcuate arrow 40). The unrolling strip 18 of roofing material is placed on the roof deck 14 such that the portion 18 a of the preceding strip is covered, and the layer 24 of adhesive is applied onto this facial portion 18 a over the fine dimension granular material 34 of that preceding strip of roofing material 18, and also extends beyond the selvage edge portion 34′ and edge 20′ to present a portion 24′ onto the roof deck 14. Recalling the explanation above, the roofing installer will use the index or guide line 30′ in order to insure that the facial portion 18 b is exposed, and the correct extent of facial portion 18 a is covered by the next successive strip of roofing material 18. As a result, and as seen in FIG. 4, the adhesive 24 is presented to and sealingly bonds to an elongate stripe 24′ of the roof deck 14 immediately adjacent to the side edge 20′.

Further, considering FIG. 4 in detail, and recalling that the layer 30 of coarse granular material of the preceding strip 18 of roofing material is a little more than one-half the width of the strip, while facial portion 18 b is a little less than one-half the width 18′, it will be seen that the side edge 20″ of the successive strip 18 is positioned such as to allow adhesive 24 to somewhat overlap the layer 30. Most preferably, there is about one and one-half inch of overlap of the adhesive 24 onto the layer 30 of course granular material. The adhesive 24 is sufficiently flowable and is such a tenacious adhesive that the course granular material 30 extending beyond the facial portion 18 b and onto facial portion 18 a does not prevent the adhesive 24 from being sealingly effective and effecting a bond in this part of the overlap joint. Of course, in the facial portion 18 a which is covered only with the layer of fine granular material 34, the adhesive 24 is effective to sealingly bond the successive strips 18 of roofing material tenaciously to one another.

This method of installation of the roofing material 18 leaves substantially all of the area of layer 30 of coarse granular material (i.e., facial portion 18 b) exposed on each of the preceding strips 18, and completely covers the fasteners 38. Thus, moisture from atop the installed strips 18 of roofing material making up membrane 16 would have to permeate between the strips 18 from the right hand side edge 20″ of a successive strip about one-half of the width of the strip in order to reach the left hand side edge 20′ of the preceding strip 18. So, the waterproof membrane 16 provides double layer coverage of the roof deck 14, and very good resistance against water penetration of the roof 10. Preferably, after each successive strip .18 of the roofing material is unrolled, partially overlapping the preceding strip of roofing material, and is fastened by fasteners 38, then a weighted roller is used over the membrane 16 in order to press the adhesive layer 24 firmly upon the facial portion 18 a of the preceding strip, and to bond the adhesive 24 onto the roof deck 14 in stripe 24′ as well. This pressing action employs the self-adhesive or pressure-sensitive nature of the adhesive 24 of the roofing material 18 to interbond the successive strips 18 of roofing material.

It is to be noted that during the unrolling of the succeeding strip 18 of roofing material 16, the protective plastic film 26 is pulled away, as is indicated by arrow 26′ on FIG. 4. Simultaneously, the roll 18 of roofing material is rolled forward, again as is indicated by arrow 40. As the roofing material 18 is applied from roll 18′ by forward motion of this roll, successive fasteners 38 are driven through the material as was explained above. Thus, the strips 18 of roofing material are secured to the roof structure 10 by fasteners, as well as by the adhesive 24 in stripe area 24′ in order to firmly secure the membrane 16 to the deck 14 of the roof structure. Also, the adhesive layer 24 is utilized in stripe area 24′ to effect waterproof interbonding of successive strips of the material 18 to the roof deck 14, such that any moisture which might be able to penetrate under a lap joint between successive strips of the material 18 is not allowed to reach the roof deck 14 itself. That is, a stripe or area of water resistant sealing bond is effected at stripe area 24′ between the adhesive 24 of a successive strip 18 of the roofing material and the edge 20′ of an underlying strip 18 of the roofing material, and to the roof deck 14 as well. So, the roofing material 18 effects not only double layer coverage of the roof deck 14, but also provides a duality of sealing bonds. The first sealing bond is formed between successive strips of the material 18 which overlap and interbond to one another to form the membrane 16. And, the second sealing bond is formed by a successive strip of the material 18 interbonding with the roof deck 14 adjacent to the side edge of an underlying strip of the material 18. Thus, a redundancy of sealing bonds are formed by the roofing material 18 with successive strips of itself, and with the roof deck 14, in order to better prevent water penetration of the roof 10.

Moreover, it will be appreciated that the adhesive material 24 which is exposed when plastic film 26 is peeled off is effective to bond the successive layer of roofing material to the preceding layer over the entire length of the strip 18, as well as from side to side of the facial portion 18 a having a width somewhat greater than the dimension 36. This bonding of adhesive layer 24 to facial portion 36 forms an interbonding of successive strips of the roofing material 16. The result is that moisture atop the applied roofing material 16 would have to penetrate between the successive layers or strips 18 about one-half of the width of the strips 18 in order to reach the roof structure 10. Because the raw asphaltic adhesive material 24 is such a tenacious adhesive, and because it remains viscid (i.e., it can soften or re-flow) and can re-bond each time it gets hot (i.e., from sunshine on a warm day), the roof 10 has somewhat of a self-healing nature, and remains water proof for many years after the roofing material 18 is installed to form the membrane 16. The fine granular material 34 on facial portion 36 does not prevent the adhesive 24 from interbonding. Further, the thickness of adhesive layer 24 is sufficient to bridge the thickness of the strips 18 at their side edge 20′ (i.e., at the selvage edge portion 34′) so that the creation of void spaces adjacent to this side edge is avoided. Such void spaces could possibly trap moisture which would expand when heated by the sun and cause the roofing membrane 16 to bubble or blister on a hot day. However, the present inventive roofing material prevents such bubbling.

Further, because of the combination of a considerable width of the interbonding area (adhesive 24 to granular material 34 and underlying base sheet 20 and matrix 22 over lateral dimension 28—which is preferably about 20½ inches wide). And this width combined with the viscid (or hot re-flow or re-softening) characteristic of the raw asphaltic adhesive 24, along with the secure attachment of the membrane 16 to the roof deck by fasteners 38. And combined with the additional sealing attachment effected as well by the adhesive 24 in bonding stripe area 24′, it is to be understood that differential thermal expansions and contractions between the roof structure 10 and the membrane 16 are well resisted or tolerated, and do not lead to separations of the strips 18 and leaking of the roofing membrane 16.

Those skilled in the art will further appreciate that the present invention may be embodied in other specific forms without departing from the spirit or central attributes thereof. Particularly, the extent of overlap of successive strips of a roll roofing material according to this invention need not be the one-half overlap described according to the most preferred embodiment. That is, an overlap of successive strips of one-third or less of the width dimension of each strip may be found to be acceptable and to make a successful roof structure in certain locations, and according to the desired service and life for a particular roof. However, in that case, the double-coverage feature of the most preferred exemplary embodiment would not be obtained. To recap that most preferred embodiment once again, the width dimension is 39½ inches, and the portions 18 a and 18 b respectively have widths of 20½ inches and 19 inches. The width of the layer 30 of coarse granular material is somewhat more than 19 inches, and the width of layer 34 (including selvage edge portion 34′) makes up the remainder of the upper face of the roofing material strip 18. On the underside of the roofing material strip 18, the width 28 of adhesive layer 24 is preferably 20½ inches, and the width of fine granular material layer 34″ is 19 inches. Thus, the stripe area 24′ of adhesive 24 presented to the roof decking 14 and sealingly interbonding with this roof decking is at least one-half (½) inch, nominally is about one inch, and may alternatively be about 1½ inches, in view of the tolerances obtainable in the manufacture of roofing materials. Because the foregoing description of the present invention discloses only a particularly preferred exemplary embodiment of the invention, it is to be understood that other variations are recognized as being within the scope of the present invention. Accordingly, the present invention is not limited to the particular embodiment which has been described in detail herein. Rather, reference should be made to the appended claims to define the scope and content of the present invention. 

1. A method of providing a roll roofing material of the self-adhesive type for application to a roof so as to effect a duality of sealing bonds, the roll roofing material in plural successive strips effecting on the one hand a sealing bond to itself, and on the other hand effecting a sealing bond of each strip to the roof, said method including the steps of: providing a roll roofing material in the form of an elongate strip of inorganic fibrous material permeated with an asphaltic matrix; dividing an upper side of the elongate strip into two elongate lateral facial portions each about one-half the width of said elongate strip; providing a covering coating of protective coarse granular material on one of said lateral facial portions, and providing a coating of fine-dimension granular material on the other of said lateral facial portions which is sufficient to prevent self adhesion of successive wraps of the strip of roofing material when rolled on itself; dividing an underside of said elongate strip of roofing material into two elongate lateral parts one of which is wider than the other by a selected lateral dimension; on the wider of said two elongate lateral parts providing a coating of an asphaltic adhesive, and on the narrower of said two lateral parts providing a coating of fine-dimension granular material effective to prevent self adhesion of successive wraps of the strip of roofing material when rolled on itself; and providing for installation of said roll roofing material on a roof in successive partially overlapping strips each having a substantial portion of said coarse granular coating upwardly exposed, and such that the wider lateral part of a successive strip of the roofing material, and said asphaltic adhesive thereon, overlap said other lateral facial portion of a preceding strip of the roofing material to on the one hand sealingly interbond thereto by action of said asphaltic adhesive, and to also extend beyond said preceding strip of roofing material by substantially said selected lateral dimension to on the other hand adhesively contact the roof and sealingly interbond thereto.
 2. The method of claim 1 further including the step of providing a removable release sheet on said layer of asphaltic adhesive.
 3. The method of claim 1 further including the step of providing a longitudinal guide mark on said upper side of said roll roofing product in said layer of course granular material, whereby said guide line provides for an edge of a next successive strip of the roll roofing material to be aligned to overlap substantially one-half of a preceding strip of the roll roofing material.
 4. The method of claim 1 further including the step of securing each strip of said roll roofing material to said roof using fasteners penetrating said other facial portion.
 5. The method of claim 4 wherein said step of securing each strip of said roll roofing material includes the step of providing for plural laterally spaced apart elongate lines of longitudinally spaced apart fasteners.
 6. The method of claim 5 wherein said step of providing plural laterally spaced apart lines of fasteners includes the step of providing three lines of longitudinally spaced apart fasteners.
 7. The method of claim 6 wherein said step of providing three lines of longitudinally spaced apart fasteners includes the step of providing two lines of fasteners with each fastener longitudinally spaced apart from the next by substantially 12 inches.
 8. The method of claim 6 wherein said step of providing three lines of longitudinally spaced apart fasteners includes the step of providing a central line of fasteners with each fastener longitudinally spaced apart from the next by substantially 18 inches.
 9. The method of claim 1 further including the step of providing said other facial portion with an elongate selvage edge portion adjacent to a side edge of said strip of roll roofing material, and configuring said elongate selvage edge portion to have a thickness which is less than the remainder of said other facial portion.
 10. A method of providing two ply coverage of a roll roofing material on a roof by use of a roll roofing material of the self-adhesive type in plural successive and partially overlapping strips so as to also effect a duality of sealing bonds, the roll roofing material in plural successive strips effecting on the one hand a sealing bond to itself, and on the other hand effecting a sealing bond of each of said plural strips to the roof, said method including the steps of: providing a roll roofing material in the form of an elongate strip of inorganic fibrous material permeated with an asphaltic matrix; dividing an upper side of the elongate strip into two elongate lateral facial portions a wider one of which is a determined dimension wider than the other facial portion; providing a covering coating of protective coarse granular material on said one facial portion, and providing a coating of fine-dimension granular material on the other facial portion, which coating of fine-dimension granular material is sufficient to prevent self adhesion of successive wraps of the strip of roofing material when rolled on itself; dividing an underside of said elongate strip of roofing material into two elongate lateral parts one of which is wider than the other by a selected lateral dimension, the one lateral facial part not being congruent with the one lateral facial portion; on said one lateral facial part providing a coating of an asphaltic adhesive, and on the other of said lateral facial parts providing a coating of fine-dimension granular material effective to prevent self adhesion of successive wraps of the strip of roofing material when rolled on itself; and installing said roll roofing material on a roof in successive partially overlapping strips each having a substantial portion of said coarse granular coating upwardly exposed, such that the one lateral facial part of a strip of the roofing material, and said asphaltic adhesive thereon, overlaps said other lateral facial portion of a preceding strip of the roofing material to on the one hand sealingly interbond thereto by action of said asphaltic adhesive while said one lateral facial portion of the successive strip of roofing material overlies the other lateral facial portion of a preceding strip of the roofing material to provide two ply coverage of the roof, and said one lateral facial part also extending beyond said other lateral facial portion of said preceding strip of roofing material by substantially said selected lateral dimension to on the other hand adhesively contact the roof and sealingly interbond thereto.
 11. The method of claim 10 further including the step of providing a removable release sheet on said layer of asphaltic adhesive.
 12. The method of claim 10 further including the step of providing a longitudinal guide mark on said upper side of said roll roofing product in said layer of course granular material, whereby said guide line provides for an edge of a next successive strip of the roll roofing material to be aligned to overlap substantially one-half of a preceding strip of the roll roofing material.
 13. The method of claim 10 further including the step of securing each strip of said roll roofing material to said roof using fasteners penetrating said other facial portion.
 14. The method of claim 13 wherein said step of securing each strip of said roll roofing material includes the step of providing for plural laterally spaced apart elongate lines of longitudinally spaced apart fasteners.
 15. The method of claim 14 wherein said step of providing plural laterally spaced apart lines of fasteners includes the step of providing three lines of longitudinally spaced apart fasteners.
 16. The method of claim 15 wherein said step of providing three lines of longitudinally spaced apart fasteners includes the step of providing two lines of fasteners with each fastener longitudinally spaced apart from the next by substantially 12 inches.
 17. The method of claim 15 wherein said step of providing three lines of longitudinally spaced apart fasteners includes the step of providing a central line of fasteners with each fastener longitudinally spaced apart from the next by substantially 18 inches.
 18. The method of claim 10 further including the step of providing said other facial portion with an elongate selvage edge portion adjacent to a side edge of said strip of roll roofing material, and configuring said elongate selvage edge portion to have a thickness which is less than the remainder of said other facial portion.
 19. A roll roofing product of the self-adhesive type configured for installation on a roof in plural successive and partially overlapping strips, said roll roofing product comprising: an elongate strip of inorganic fibrous sheet material permeated with an asphaltic matrix; said elongate strip including an upper side divided longitudinally into two elongate lateral facial portions, a wider one of said two elongate lateral facial portions being a determined dimension wider than the other of said two elongate lateral facial portions; a covering coating of protective coarse granular material carried on said one lateral facial portion, and a coating of fine-dimension granular material carried on the other of said lateral facial portions, said coating of fine-dimension granular material being sufficient to prevent self adhesion of successive wraps of the strip of roofing material when rolled on itself; said elongate strip also including an underside divided into two elongate lateral facial parts one of which is wider than the other by a selected lateral dimension, the one lateral facial part not being congruent with the one lateral facial portion; a coating of an asphaltic adhesive on said one lateral facial part, and a coating of fine-dimension granular material on the other of said lateral facial parts, said coating of fine-dimension granular material being effective to prevent self adhesion of successive wraps of the strip of roofing material when rolled on itself.
 20. The roll roofing product of claim 19 further including a removable release sheet on said layer of asphaltic adhesive.
 21. The roll roofing product of claim 19 wherein said determined dimension is at least one-half inch.
 22. The roll roofing product of claim 19 wherein said selected dimension is at least one-half inch.
 23. A roll roofing product comprising: an elongate strip of inorganic fibrous sheet material permeated with an asphaltic matrix; said elongate strip defining a pair of upper elongate longitudinal facial portions each about one-half as wide as the strip of sheet material; one of said pair of upper elongate longitudinal facial portions carrying a covering layer of protective coarse granular material, and the other of said pair of upper elongate longitudinal facial portions carrying a coating of fine-dimension granular material sufficient to prevent self adhesion of successive wraps of the strip of roofing material when rolled on itself; said elongate strip further defining a pair of lower elongate longitudinal facial parts each about one-half as wide as the strip of sheet material; one of said pair of lower elongate facial parts carrying a coating of an asphaltic adhesive, and the other of said pair of lower elongate longitudinal facial parts carrying a coating of fine-dimension granular material effective to prevent self adhesion of successive wraps of the strip of roofing material when rolled on itself. 